Pursuing the life of an ascetic and munching on supplements in the hope that you'll still be around when the singularity hits - it's not too far from giving yourself to religion.
Name three. And please note that Voldemort doesn't count because he's not a real person.
I would reverse your question and name people who, even though they could have lived more, they chose not to do so: I will name a heavyweight: Albert Einstein
If they're not signed up for cryonics, at their income level, I don't buy that they're actually consumed by anything remotely resembling a quest for technological immortality, as opposed to merely trying to grab onto their fading youth using conventional and uninteresting methods.
http://www.amazon.com/Tuck-Everlasting-Sunburst-Natalie-Babb...
Yes, it's aimed toward 10 year olds, but it's pretty relevant here. It'd probably take less than an hour for an adult to read, which should be just a blip on your quest for immortality. :-)
This is a synopsis of a short story by Larry Niven.
I also know some sad people in quest of immortality, but they were generally sad before they found out about that stuff. In general, I think that seeking immortality has surprisingly little effect on your prior personality. It's just something you do if you have enough of a logical frame of mind to think "Life is good, death is bad, and Voldemort isn't a real person", but the logical mind is the cause, not the effect.
The phenomenon of people getting too involved in X to enjoy life is a common theme for stories. When X has to do with the extension of life, there's a pleasingly ironic self-reference. So really, the moral lesson of such stories has to do with life balance generally, and the ironic twist is more akin to a rhyme in a poem.
Not seeking life extension at all is definitely not rational. Perhaps it's rational not to seek it personally, but that's a personal choice. I think our society should seek life extension as an ethical choice.
Thank you for making a testable prediction. Your hypothesis is thereby falsified.
"Polyamory is usually one guy and more women and is usually quite the sexist thing. "
Good heavens, what sort of culture-free hole were you raised in? Do you know anyone polyamorous in real life?
"Seeking life extension is at the current point of science not really rational."
And there you have it. If you're anti-fun, you're probably also anti-life.
Even without the singularity argument, a healthy lifestyle can help avoid some really miserable life experiences. Heart disease, for example, can make it difficult to enjoy taking a nice walk.